Sunday, March 1, 2009

Tracing a Gene

Many fantasy novels feature a black wolf as a harbinger of something, usually bad: disaster or evil or dark magic. Now science has traced the gene that makes wolves black. The gene appears in the wild mainly in North America, and did not appear here until after humans crossed the Bering land bridge 15,000 years ago, bringing their dogs with them. Those dogs carried the black-coat gene, which is missing three nucleotides found in the "normal" gene. The dogs then mated with native wolves, and some of the pups had black coats. All this was deduced by a team of geneticists at Stanford, who studied the genomes of a large number of wolves and dogs. Their conclusion is that humans indirectly caused the black wolves, which we then made a symbol of evil. Talk about blaming the victim!However, what's interesting to me is that the mutated allele, called beta-defensin, belongs to a family of genes thought to be involved in fighting infection. Are black-coated dogs and wolves less susceptible to infection than other colors? Is that why, in the distant past, we found them particularly magical?The surprises coming out of genetics are fascinating. Our entire history as a species is there, as well as the histories of other species. If I could afford it, I would have my own genome analyzed -- just from curiosity about what I might learn about my great-great-great grandmother. Hmmm.... If I got a story out of the results, perhaps I could even write the analysis off as a business expense?